NATURAL SYSTEMS FOR PREVENTING CONTAMINATION AND GROWTH OF MICROORGANISMS IN FOODS

Food-borne illness is a vast and costly worldwide problem. Although co mplex, it may be divided into two major types of animal and human dise ase: intoxication caused by toxic substances in food and secondly, inf ection, caused by microorganisms. Toxic substances may be already pres ent in foods, or they may be produced by microorganisms through contam ination and proliferation in food. Prevention of the invasion of foods by microorganisms may be achieved by effective use of intrinsic facto rs found in plants and animals. These factors include pH, moisture con tent, oxidation-reduction potential, nutrient content, biological stru ctures, and antimicrobial constituents. A second type of natural prote ction is that of microbial antagonism. Research work discussed include s that done in the author's laboratories involving tannic acid and mic robial antagonism against Listeria monocytogenes in milk. The safety o f all natural mechanisms of defense is important economically and in p ublic health. We predict that the use of antimicrobials occurring natu rally in foods and safe microbial antagonism will receive more attenti on in future food safety research.